SCIENCE Q & A

Published January 26, 2013 - 4:14am Last Updated January 26, 2013 - 8:52am

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Calculating the age of the universe complex

Q: When I read that “the universe is 13.7 billion years old,” I wonder: Don’t scientists use some more universal measurement than years, something not tied to the orbit of one tiny planet?

A: Modern measurement of time builds on the second, based on atomic oscillation, rather than on the variable time it takes the Earth to orbit the sun.

As the National Institute of Standards and Technology explains, a second has been defined since 1967 as the time it takes for a cesium atom to oscillate 9,192,631,770 times between two radiation states.

An alternative unit called the cosmic year has been suggested, based on the sun’s orbit around the centre of the Milky Way galaxy about once every 225 million years.

But this “year” is not routinely used by cosmologists, said Andrew J.S. Hamilton, a professor of astrophysics at the University of Colorado.

“The age of the universe is not something that is directly measured by astronomers,” Hamilton said. “What they measure is the rate of expansion of the universe, as measured by the so-called Hubble parameter” — named for the 20th-century astronomer Edwin Hubble, who was one of the earliest to calculate the expansion rate by noticing that the more distant galaxies are receding at faster speeds.

A value called the reciprocal of the Hubble parameter is approximately equal to the age of the universe, or 13.7 billion years, he added.

Flu vaccine appears to reduce ear infections

Q. Does the flu vaccine reduce the likelihood of ear infections in children?

A. For many children, flu season means an increased risk of ear infections as well.

Although many people do not realize it, the middle ear has a direct link to the upper respiratory tract: the auditory, or eustachian, tube. Infections in the nose or sinus cavities thus can spread to the ear.

Ear infections are a common scourge of childhood. Most children under the age of 8 will have at least one, and over a quarter will experience them chronically.

Although ear infections can strike at any time, they do show some seasonal variation. In a large study published in December, researchers looked at more than 270,000 cases of acute ear infections. They found that ear infections increased along with the flu and illnesses caused by two other respiratory viruses (though not the common cold).

So does that mean that vaccinating against the flu might prevent ear infections in children? Some researchers think so.

In a report published in 2011, scientists pooled data from eight randomized studies of 24,000 children between the ages of six months and seven years. They found that those who received the FluMist vaccine, a nasal spray made with live but weakened flu virus, had a significantly lower risk of acute ear infections compared with children who received a placebo. Among children who ultimately got the flu, those who had been vaccinated had a 40 per cent reduction in ear infections compared with children who were given a placebo.

A study published last year also found that the flu vaccine reduced the incidence of acute ear infections in children. FluMist appears to be more effective than the shot, but scientists say more research is needed.